Modified Smith predictor for long time thermal processes

This paper proposes a new type of predictor to equip automatic PID controllers. The presented predictor is designed to ensure an adequate control for long time processes, whose evolution in time should be controlled in closed loop. At these processes, as a result of automatic control, the outputs followed run within limits for a period of time which, sometimes, exceeds the period in which the system would stabilize if at its entry should be applied to a step control. Therefore the efficiency of a classic predictor (Smith type for example) is much diminished with time. The proposed predictor starts from a classical scheme of Smith predictor, but changes the concept of its way of working, to ensure a constant efficiency for the entire period of time that the process needs.